Avian Metapneumovirus Infection Rhinotracheitis (Swollen Head Syndrome SHS) in Laying Hens
Observed Clinical Signs Happenings
Egg drop
- Egg production drops gradually
- In some cases, egg drop may be not detected
Visibly sick birds
- Few visibly sick birds
- Usually, less than 4% of the flock are affected.
Mortality
- Low mortality or increases gradually
- Mortality rarely exceeds 2%
Dead Birds
- Skinny body (Poor body fleshing condition)
Respiratory
- Respiratory signs spread fast
- Widespread respiratory signs are usually present
Neurological /Nervous
- As a result of secondary E. coli infection
- Torticollis
- Cerebral disorientation
- Opisthotonus
Head Comb Wattles Face Nostrils Sinuses Mount Beak Earlobes
- Swelling of the Head
- Swelling of the periorbital and infraorbital sinuses
Body Parts (Neck wings breast abdomen shanks legs hocks feet joints vent skin)
- Laying hens may also present with prolapsed oviducts due to violent coughing
Shell quality
- This infection may also affect the quality of eggs
- Pale or loss of colour in brown-shelled eggs
- Misshapen eggs
Avian Metapneumovirus Infection Rhinotracheitis (Swollen Head Syndrome SHD) in Laying Hens show, exhibit, or manifest any of the following clinical signs happenings:
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Observed Clinical Signs Happenings |
ALWAYS |
NEVER |
SOMETIMES |
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Egg drop |
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Egg production declines rapidly |
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Egg production drops gradually |
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Mortality above the standard |
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Low mortality or increases gradually |
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High mortality or increases rapidly |
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Dead birds |
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Dead birds in Good bodily condition |
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Dead birds in Poor bodily condition |
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Visibly sick birds |
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Few visibly sick birds |
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Many visibly sick birds |
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Flock behaviour activity change |
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Droppings abnormalities |
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Respiratory abnormalities |
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Respiratory signs spread fast |
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Respiratory signs spread slow |
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Neurological Nervous |
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Lameness or unusual movements, incoordination, reluctance to move |
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Eyes abnormalities |
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Head: Comb Wattles Face Nostrils Sinuses Mount Beak Earlobes (except eyes) |
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Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression |
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Feathers abnormalities |
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Feed Consumption Changes |
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Diet or Feed Changes (Recent Feed delivery, Recent formulation /diet, Other silo or improper storage, another feed brand) |
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Shell quality |
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Internal Egg quality |
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* Sometimes has not been observed or measured the neurological or nervous changes yet or inadequacy of monitoring systems, and even the course time of the disease *Sometimes has not been observed the Body parts abnormalities (prolapsed oviducts) yet or depend on the course time of the disease *Sometimes has not been observed or measured the shell quality changes yet or inadequacy of monitoring systems, and even the course time of the disease
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- Causing Agents
- Avian metapneumovirus infection. Avian Metapneumoviruses are members of the subfamily Pneumoviridae, belonging to the family Paramixoviridae
- Affected Systems/Organs
- Respiratory, Reproductive and Neurological System
- Spread
- Transmission is rapid through aerosols via the respiratory route. Transmission from parents is uncertain. Contaminated objects.
- Mainly Affects
- Egg production, Egg quality and Liveability
- Solution
- Control respiratory stressors. Multivitamins. Good management practices. Good biosecurity.
- Suggested Actions
- Can be confirmed with clinical signs and gross lesions
- Can be managed with feed additives, off-the-shelf medications
- Diagnosis should be confirmed with rapid assays and/or a certified laboratory
- Veterinary intervention is recommended
Impact on Egg quality
Impact on Liveability
Impact on Production
Overall Economic Impact
- Y.M. Saif.2008.Disease of Poultry. 12th Edition. page 103
- David E. Swayne. 2013. Diseases of Poultry 13th Edition. page 115